Sliding calipers are handheld tools used to very precisely measure the distance between two symmetrically opposing sides. They are frequently used in checking or inspecting dimensions of parts and/or assemblies in metal, plastic, and woodworking fields. Conventional handheld sliding calipers are relatively inexpensive, but they are not suitable for many applications, such as the positioning of a sawtable fence, a milling machine travel table or spindle, or a metal lathe carriage, top slide, or tailstock. Stated another way, conventional handheld sliding calipers are generally not suitable as a generic machine positioning device.
Typically, precise movements of machining tools such as sawtable fences, milling machine tables, and metal lathe carriages are made by recording the relative positions noted by crude markings adjacent to a hand wheel or hand crank on the machine. Alternatively, precise single-application devices, designed specifically for a sawtable, milling machine, or metal lathe and typically costing hundreds of dollars, can be obtained and installed on these machines (or in some cases are purchased with the machine).
There is a need for an inexpensive, multiple-application accessory that can adapt a conventional handheld sliding caliper for use in making precise measurements on a wide variety of wood, metal, and plastic-working machines. There is also a need for an accessory for spring-biasing the movable frame of a conventional sliding caliper for two-way positioning detection.